sandwell



(No Model.) 2 SheetsSheet 1.

W. D. SANDWELL.

DYNAMO ELECTRIC MACHINE.

No. 405,507. Patented June 18, 1889.

L [ill 6712072 ,0 d MMQ MEMLL J mwwwx Witnesses;

(No Model.) 2 Sheets-Sheet 2.

W. D. SANDWELL. DYNAMO ELECTRIC MAGHINE.

No. 405.507, Patented June 18, 1889.

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UNITED STATES PATENT OFFICE.

\VILLIAM DANTON SANDIVELL, OF HERNE HILL, COUNTY OF SURREY,

ENGLAND.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 405,507, dated June 18,1889.

Application filed February 18, 1889. Serial No. 299,744. (No model)Patented in England October 25,1887,N0.14,5421 in Germany March 14,1888, No. 45,153; in Belgium March 30, 1888, No. 81,241; in France March31, 1888, No. 189,706; in Italy June 30, 1888, XXII, 23,317, XLVI, 392;in Spain July 13, 1888, No. 8,158; in Austria-Hungary August 9,1888, No.14,880

and No. 31,608, and in Canada Febr ary 14, 1889, No. 30,776.

To aZZ whom it 727/601] concern.-

Be it known that I, WILLIAM DANTON SANDWELL, a subject of the Queen ofGreat Britain, residing at Herne Hill, in the county of Surrey, England,have invented new and useful Improvements relating to Dynamo- ElectricMachines and to Electric Motors, (for which Letters Patent have beengranted to me as follows: in Great Britain, No. 14,542, dated October25, 1887 in Germany, No. 45,153, dated March 14, 1888; in Belgium, No.81,241, dated March 30, 1888; in France, No. 189,706, dated March31,1888; in Italy, Vol. XXII, No. 23,317, Vol. XLVI, No. 392, dated June30, 1888; in Spain, No. 8,158, dated July 13, 1888; in Austria- Hungary,Nos. 14,830 and 31,608, dated August 9, 1888, and in Canada, No. 30,776,dated February 14, 1889,) of which the following is a specification.

My invention relates to dynamo-electric machines and to electric motors.

In using an electric motor it is well known that after a time thearmature will become heated. For this reason two machines are frequentlyemployed, so that after the armature of one machine has become heated itmay be allowed to stand while it cools, the other machine being employedin the meantime. This arrangement, however, is disadvantageous, andchiefly for the reason that it is very expensive.

The chief object of my present invention is to obtain all the advantagesof tWo n1achines at a lower cost than heretofore; and 'to this end itcomprises the improvements as hereinafter described.

According to my said invention I employ two armatures in combinationwith one set of field-magnets, so that after one armature is heated itcan be replaced by the other. In practice I find it very advantageous tomove the magnets relatively to the arma'tures; but it is obvious that Ican also move the armatures relatively to the magnets. The magnets orthe armatures may be moved by any suitable means-for instance, byscrew-gear ing or by racks and pinions.

In addition to the advantages hereinbefore mentioned, the presentinvention possesses the further advantage that the armature which is notin use is not inclosed within the field-magnets, so that the air is freeto circulate around the same, whereby the cooling takes place morerapidly than would otherwise be the case.

To enable my invention to be clearly understood,I will describe howitmaybe carried into practice by reference to the accompanying drawings,in which- Figure 1 is a plan of a motor constructed according to myinvention, and Fig. 2 is an end view of the same. Fig. 3 is a plan Viewillustrating the modification of my invention wherein the armatures areadapted to be moved relatively to the field-magnets.

a is the frame of the motor, which frame has brackets 19 (by means ofwhich the motor can be suspended or upon which it is supported) andslide-bars c.

d cl are the field-magnets, which at their ends are provided withsockets 6, adapted to slide upon the bars 0, and f f are rack-bars,which are connected with the said field-magnets and in engagement withrack-pinions g g on a shaft h, so that when the said shaft is rotatedthe field-magnets can be caused to slide upon the bars 0 in one or otherdirection, as desired.

c'is the armature-shaft, which carries two armatures j k, the said shaftbeing supported in hearings in the frame a.

Z Z are the commutators of the armaturesj 70, respectively, and m m 'n nare sets of brushes adapted to bear upon the same, the brushes m m beingdesigned to make contact with their respective commutators when thearmatures are rotating in one direction and the brushes n n when theyare rotatingin the opposite direction.

It will be noticed that each commutator has two sets of brushes inconnection with it, so as to enable the armatures to be rotated inopposite directions, if desired; but it is obvious that only one set ofbrushes is necessary when rotation is only required in one direction. Incase either armature becomes incapacitated, the provision of two sets ofbrushes enables the remaining armature to be rotated in both directions.

In order to allow of placing one or other of the sets of brushes incontact with the commutators, as desired, the brushes m m n n of eachcommutator are mounted upon a fourarmed bracket 0, fixed to the frame ofthe machine, and extensions on the brush-carriers are connected by links19 p to two arms q q of a three-armed lever having a slight rotarymovement relatively to the shaft 1 The other arm '1' of the saidthree-armed lever is connected with a rod 5, through the medium of whichthe three-armed lever can be moved. \Vhen the rod .9 is moved in onedirection, the brush carriers and their brushes are caused to oscillateupon their pivots, thus moving one set of brushes into contact with thecommutator and the other set out of contact, and Vice versa.

The movement of the threearmed lever may be produced by any desirablemeans. As shown in the drawings, however, the movement is effectedautomatically at the same time that the field-magnets are being movedfrom one armature to the other. The movement in this case is effectedthrough the medium of a pinion 2, engaging with the toothsector a,secured to a shaft it, upon which are fixed two levers 2:, attached attheir free ends to the rods 5 s of the respective commutators.

The modification of my invention wherein the armatures and their shaftare movable relatively to the field-magnets is illustrated in Fig. 3. Inthis figure the armature-shaft is supported in bearings in the bracketsof, and is connected with the driving-pulley as by means of aspline-joint y. The armatures j 7; are mounted in a sliding frame 1having the extensions if, which slide upon the rods .2 .2. One of theserods is screw-threaded, so that by rotating the same the sliding framewith the armature can be moved.

I would observe that I do not confine mymovable with respect to theother, substan-.

tially as described.

2. In an electric motor, the combination, with the movablefield-magnets, of two armatures for the same, substantially asdescribed.

3. In an electric motor, the combination, with the field-magnets, of twoarmatnres, the said magnets being movable longitudinally of thearmature-shaft, substantially as de scribed.

4. In an electric motor, the combination,

with the field-magnets and two armatures for the same, said magnetsbeing movable longitudinally of the arn'iature-shaft, of a commutatorfor each armature, each commutator being provided with two sets ofbrushes, substantially as described.

5. In an electric motor, the combination, with the field-magnets and twoarmatures for the same, said magnets being movable longitudinally of thearmature-shaft, of a commutator foreach armature, each commutator beingprovided with two sets of pivoted brushes, the brushes of one set beingconnected to those of the other set, whereby a movement of one set intoposition Withdraws the others, substantially as described.

WllllllAll DANTON SANllWllllh.

IVitnesses:

G. F. REDFERN, JoHN E. BoNsmELD.

